As previously mentioned, it is known to form a pipeline over-length, and, then to close the end of the pipe by an end cap or end fitting, the end cap either being threaded onto the pipe end and sealed, or, secured thereto by a segmented pipe coupling.
This, however, represents a wastage of materials in that the pipe must terminate axially beyond the last sprinkler head in the assembly.
This problem previously has been addressed, an end fitting being known, as is illustrated FIG. 1 of the accompanying drawings, which is comprised of radially extending annular cap, the central opening of which communicates with an outlet pipe, that of necessity, must extend arcuately in a 90.degree. angle for the outlet thereof to extend perpendicular to the pipe axis, the pipe terminating in an internally threaded end collar within which the threaded shank of a sprinkler head is secured.
Typically, the pipes of such pipelines have a minimum internal diameter of between 1.5" and 2.5". Also, typically, the outlets of such end fittings must have a bore of at least 0.5" in order to provide adequate water flow to the sprinkler head. Further, the sprinkler must be assembled onto the pipe fitting at a distance sufficient from the pipe to permit the installation of a sprinkler guard on the sprinkler head.
This requires that the radius of curvature of the outlet pipe extending from the end flange of the end fitting must be on a radius of curvature at least equal to the radius of the pipe.
The end fitting, however, is not nearly as robust as the pipe itself. Thus, impact on the end fitting during assembly of the sprinkler system can cause bending or breakage of the outlet pipe of the end fitting. Additionally, the end fitting presents an appearance which is less than attractive.
A major disadvantage with such known end fittings is that while the end flange of such fittings must block off a surface area of 4.9 square inches, the outlet pipe itself only presents an outlet opening of 0.20 square inches. Thus, water progressing along the pipe to the sprinkler head, when the sprinkler head is active, encounters a radial end wall, which extends perpendicular to the axis of the pipe, and, which represents a major source of pressure losses, turbulence and eddy currents, this in turn resulting in a loss in the pressure of fluid exiting the central aperture. Further, as the fluid exiting the central aperture, must itself be changed in direction by 90.degree., further pressure losses are encountered in the outlet pipe to the sprinkler head. Additionally, pressure losses are caused by the contraction loss from the pipe diameter to the central aperture diameter.
These losses in dynamic and static pressure result in the sprinkler head at the end of the pipe being incapable of operating as efficiently as the other sprinklers in the line. Regulatory and insurance requirements require a determined minimum flow from any one of the sprinkler heads, regardless of the location of that sprinkler head in the sprinkler system. This in turn mandates an oversizing of the supply pipe with the additional cost thereon.